Telephone system.



PATENTED OCT. 10, 1905.

C. E. EGAN.

TELEPHONE SYSTEM.

APPLICATION FILED SEPT.26, 1899.

W/ T/V E 385 S UNITED STATES PATENT OFFICE.

CHARLES EDIVAR D EGAN, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGIINIENTS, TO THE EGAN ELECTRIC AND TELEPHONE MANUFAC- TURING COMPANY, OFPETERSBURG, ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Oct. 10, 1905.

Application filed SBPlZGlIlbCI 26, 1899. Serial N0. 731,712.

To //Z 10710111, if nm/y concern.-

Be it known that I, CHARLES EDWARD Eomyof Chicago, Illinois,haveinvented a new and Improved Telephone System, of which 5 the followingis a full, clear, and exact description.

This invention relates to improvements in telephone systems in whichanumber of telephones are arranged on a single circuit; and

I the object is to provide a simple means whereby the operator at thecentral station may cut out the coil and bell circuits of all theintermediate telephones while conversation is held between twosubscribers at the remote stations, thus reducing the resistance in thetalking-circuit.

I will describe a telephone system embodying my invention and then pointout the novel features in the appended claims.

Reference is to be had to the accompanying drawing, forming a part ofthis specification, in which the figure of drawing is a diagrammaticview of a portion of a telephone system, showing the jack and switchmechanism of the central station and a subscribers telephone connectedin accordance with my invention. 1

Referring to the drawing, 1 2 designate the main or line wires. Thesewires connect, respectively, with circuit-closers arranged at thecentral office and consisting of contacts 3 4;

which for convenience in operation, as will be hereinafter described,are connected by a cross-piece 5 of insulating material. These contacts3 and I normally engage the contacts 6 and T, from which wires 8 and 9extend through the spring-jack 10 and the electromagnet 11 on theswitchboard. The armature 12 for the electromagnet 11 extends through anopening in the switchboard .11 and normally engages with a drop 13,mounted to swing downward on the switchboard to disclose the number of asubscriber or a person calling central.

The line 1 2 is supposed to be a series partyline, and any one of theparties thereon may call central or any other party. The so-calledcentral office, however, may well be, as it often is in practice, one ofthe subscribers stations.

Arranged in the casing of each telephone or adjacent thereto are twoheating-chambers 14 and 15, which consist of thin copper, preferablycorrugated, so that they can be easily expanded by heat to shift ashunt-switch. Arranged in the chamber 14: is a heating-coil 1b, and oneend of this coil has connection with a wire 17, leading to the main wire2, and in this wire 17 is arranged the generator 18 and the ringer 19.The other end of the coil 16 connects by a wire 20 with the contact 21in the telephone, which is normally engaged by the receiver-hook 22, andfrom the receiver-hook 22a wire 23 leads to the main wire 2.

From the contact 24, adapted to be engaged by the receiver-hook when inits upper position, a wire 25 leads through the transmitter 26 to thebattery 27, the primary 28 of the induction-coil, and thence to acontact 29, adapted to be engaged by the receiverhook. The receiver isarranged in a circuit having connection through the wire 31 with themain-line wire 2, and in this receivercircuit is the secondary 32 of theinductioncoil, from which a wire 33 extends to the contact 29.

A heating-coil 34 in the chamber 15 is connected at one end through awire 35 with the main-line wire 2, and the other end of said coil isconnected by a wire 36 with a shuntswitch consisting of a metal plate37, mounted to swing on a pivot 38 and adapted to engage with a contact39, from which a wire 40 leads to the main-line wire 2. A contact 41 ismounted on a block 42, secured to the swinging circuit-controller 37,and this contact 41 is adapted to be engaged with a contact 43 undercertain conditions, as will hereinafter appear. The contacts il and 43are connected by shunt-wires 4:4 and 4:5 with the circuit containing theheating-coil 16.

The controller37 has an upwardly-extended arm 46, designed to serve asan indicator to show the position of the switch 37-that is, when in oneposition the upper end of said arm will be seen through an opening 47 inthe telephone-case and when in the other position it will be seenthrough an opening 48 in the telephone-case.

In operation when one subscriber desires to converse with another heturns the handle of the generator 18 of his telephone, which sends thecurrent through the main wires, energizing the electromagnet 11 andcausing the drop 13 to fall. The operator at the central station uponreceiving notice as to the subscriber with whom communication is desiredplaces a connecting-plug in the spring-jack and in the usual manner,with a connection plug and cord, connects the two telephones. She thendepresses the keys 3 and 4: against the contacts 19 and 50,respectively, which latter are connected in circuit with battery 51. Thecurrent from the battery passes to line 1, to return-line 2, and at eachstation except that calling by the following path: through ringer 19,generator 18, wire 17, to the heating-coil 16 in chamber 15, thencethrough wire 20, contact 21, hook 22, and wire 23 to line 2. The passageof the current through coil 16 at each station heats chamber 14, causingthe same to expand, rocking lever or rod 52, which in turn comes intocontact with and causes switch 37 to swing about its pivot. The movementof said switch to the left brings it against contact 39, and at the sametime contacts 41 and 43 are brought together, thereby shortcircuitingcoil 16 and bringing coil 3 1 into line, the battery 51, however, beingcut out before coil 3 1 is heated sufiiciently to act. As the switchswings over in the manner just described its upper end a7 comes oppositethe opening 18, thereby indicating to the subscriber at any stationother than the one already in use that the line is busy. Furthermore, byreason of the switch making contact with 39 all others in the lineexcepting those in use and in which the hooks 22 are elevated areshunted, thereby reducing the resistance in the talking-circuit. Thosein use will not be affected, because the hooks are up and coil 16 cutout. It is of course to be under-- stood, as stated above, that theoperator will maintain the battery 51 in circuit only long enough toheat coil 16 and cause the shifting of the parts as noted. WVhen thesubscribers are through conversing and it is desired to restore the lineand all the telephones thereon to their normal condition, the operatorwill again throw in the battery 51, and inasmuch as coil 34 is incircuit therewith the chamber 15 will expand and the switch 37 willswing back to the position shown in the drawing, thereby breakingcontact between 11 and 4:3, and 39 and the switch. The line will then bein condition for the repetition of the above operations when a furthercall is made. All

stations except those calling or called, which may have their receiversofi the hooks, are shunted. The coil 34 does not throw back the switch,because the current is cut ofl. Current would pass through coil 16 ofthe callingstation after all had hung up, but continuing would passthrough coil 34 and restore the switch.

Having thus fully described my invention, I claim as new and desire tosecure by Letters Patent 1. Ina telephone system, a telephone-circuit,telephones arranged in the circuit, heating-coils arranged in thecircuit, chambers having corrugated diaphragms adapted to be expanded byair heated by the coils, and a circuit-controller for each telephone,the said controller being operated in one direction by one corrugateddiaphragm, and in the other direction by the other corrugated diaphragm,

substantially as specified.

2. The combination with a telephone, of a circuit-controller comprisinga metal plate adapted to form part of the circuit, chambers arranged inthe circuit and having corrugated expansive inner walls, swinging rodshaving connection with said walls, a circuit-controller adapted to beoperated by said rods, heating-coils in the chambers, and means at acentral office for controlling the heating-coils, substantially asspecified.

3. In a telephone system, two opposite chambers having expansivecorrugated inner walls, heating-coils in said chambers, the saidheating-coils being located in shunt-circuits from the main line, andmeans under control at a main oiifice for controlling the currentpassing through the heating-coils, substantially as specified, I

4. The combination with a telephone, of a circuit-controller comprisinga swinging plate, means, comprising heating-coils, for causing movementsof said controller, and a circuitcloser carried by the controller fordirecting a portion of the current through one of the coils, should theother coil become overheated, substantially as specified.

CHARLES EDWARD EGAN.

I/Vitnesses:

F. G. BATTLE, H. P. MARKHAM.

